Change the use of #if / #endif

Previously, the documents item jump bar could get confused by the use of `#if` / `#endif` directives in the middle of an `if` statement. Thus, if you pulled down the document items jump bar (either by clicking on it or pressing <kbd>control</kbd>-<kbd>6</kbd>), you'd see an incomplete list of the methods (highlight added):

![before1](https://f.cloud.github.com/assets/1530768/1896695/f5ae5360-7bb0-11e3-8d32-862383664f2e.png)

With this commit, `FMDatabaseQueue` and `FMDatabasePool` will show a complete list of method names:

![after1](https://f.cloud.github.com/assets/1530768/1896697/08fbd442-7bb1-11e3-8149-fc9631912456.png)

It makes it a little easier to navigate the FMDB code.